CoFe2O4 nanoparticles as efficient bifunctional catalysts applied in Zn-air battery

The transition metal compound catalysts have been taken a great part in renewable energy conversion and storage systems. Herein, we report the uniform CoFe2O4 nanoparticles with abundant oxygen vacancies and specific active surface exposed through the simple hydrothermal reaction for improving the electrocatalytic performance and stability. They show good electrocatalytic performance for hydrogen evolution reaction in 0.5 M H2SO4 with an onset potential of 20 mV, the overpotential of 45 mV (at j = 10 mA/cm(2)), and remarkable long-term stability more than 100 h at different current densities and better oxygen reduction reaction activity with lower overpotential in 0.1 M KOH. Moreover, the home-made primary Zn-air batteries, using CoFe2O4 nanoparticles as an air-cathode display the high open-circuit voltage of 1.47 V and the maximum power density of 142 mW/cm(2). The two-series-connected batteries fabricated by CoFe2O4 nanoparticles can support a light-emitting diode to work for more than 48 h.